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authorJan Kara <jack@suse.cz>2010-09-15 17:38:58 +0200
committerJan Kara <jack@suse.cz>2011-01-12 19:14:55 +0100
commitf00c9e44ad1a9660fe8cd3ca15b6cd9497172eab (patch)
treecbb47ae0d8aba9d8b3c44714b000156715cdf969 /include/linux/quota.h
parent4162cf64973df51fc885825bc9ca4d055891c49f (diff)
downloadop-kernel-dev-f00c9e44ad1a9660fe8cd3ca15b6cd9497172eab.zip
op-kernel-dev-f00c9e44ad1a9660fe8cd3ca15b6cd9497172eab.tar.gz
quota: Fix deadlock during path resolution
As Al Viro pointed out path resolution during Q_QUOTAON calls to quotactl is prone to deadlocks. We hold s_umount semaphore for reading during the path resolution and resolution itself may need to acquire the semaphore for writing when e. g. autofs mountpoint is passed. Solve the problem by performing the resolution before we get hold of the superblock (and thus s_umount semaphore). The whole thing is complicated by the fact that some filesystems (OCFS2) ignore the path argument. So to distinguish between filesystem which want the path and which do not we introduce new .quota_on_meta callback which does not get the path. OCFS2 then uses this callback instead of old .quota_on. CC: Al Viro <viro@ZenIV.linux.org.uk> CC: Christoph Hellwig <hch@lst.de> CC: Ted Ts'o <tytso@mit.edu> CC: Joel Becker <joel.becker@oracle.com> Signed-off-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'include/linux/quota.h')
-rw-r--r--include/linux/quota.h5
1 files changed, 4 insertions, 1 deletions
diff --git a/include/linux/quota.h b/include/linux/quota.h
index 94c1f03..9a85412 100644
--- a/include/linux/quota.h
+++ b/include/linux/quota.h
@@ -322,9 +322,12 @@ struct dquot_operations {
qsize_t *(*get_reserved_space) (struct inode *);
};
+struct path;
+
/* Operations handling requests from userspace */
struct quotactl_ops {
- int (*quota_on)(struct super_block *, int, int, char *);
+ int (*quota_on)(struct super_block *, int, int, struct path *);
+ int (*quota_on_meta)(struct super_block *, int, int);
int (*quota_off)(struct super_block *, int);
int (*quota_sync)(struct super_block *, int, int);
int (*get_info)(struct super_block *, int, struct if_dqinfo *);
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